The present invention relates to a body structure for a motor vehicle having at least one movable vehicle body part which is arranged along an impact load direction as well as stationary vehicle body sections which flank the movable vehicle body part and are approximately aligned in the impact load direction in front of and behind the moveable body part. Each of the movable vehicle body parts and the flanking vehicle body sections is constructed of an outer shell and an inner shell which are aligned in the impact load direction.
Passenger cars with self-supporting body structures are generally known. At least two side doors, and normally in the case of a station wagon one swivellable tail gate, are assigned to the body structure of such a passenger car. The side doors and the tail gate represent movable vehicle body parts which are flanked by stationary vehicle body sections of the body structure, particularly by A-columns and B-columns or by rear columns. In the event of a strong vehicle impact acting in the longitudinal direction of the vehicle, that is, in the event of a frontal impact or a rear impact, there is a risk that the side doors may no longer be opened without difficulty. In such cases, it may be necessary to use cutting tools in a high-cost manner in order to rescue persons from the vehicle. Particularly, when vehicle occupants are seriously injured, valuable time will be lost because of such measures. A similar situation may arise when, after a side impact, the tail gate in a rear area of the motor vehicle can no longer be opened and vehicle occupants on a third seat bench in a cargo space of the station wagon may have to be rescued.
It is an object of the invention to provide a body structure of the initially mentioned type which permits a fast rescue of vehicle occupants in the event of a strong vehicle impact.
This object is achieved by designing the outer shell of the movable vehicle body part so that it is resistant to deformation and designing the pertaining inner shell so that it is deformable, at least in sections, viewed in the impact load direction, and by designing at least one flanking vehicle body section in a correspondingly inverse manner, namely, constructing the outer shell to be deformable at least in sections and the inner shell to be resistant to deformation. The movable vehicle body part, therefore, cannot be wedged in such a form-locking manner with the adjusting vehicle body sections that opening of the vehicle body part is no longer possible. The invention is based on a recognition that the difficulties when opening side doors deformed by a frontal impact or a rear impact are the result of a form-locking wedging, particularly in the door lock area between the side door and the corresponding body structure supporting column. By stiffening the outer shell of the movable vehicle body part and with the simultaneously deformable design of the aligned outer shell of the at least one adjacent vehicle body section, a corresponding reverse deformability of the inner shell of the movable vehicle body part, and the resistance to deformation of the adjoining inner shell of the stationary vehicle body section, wedging of the adjacent faces of the vehicle body part and the vehicle body section, which hinders an opening of the vehicle body part, can not occur. On the contrary, the faces will rotate during deformation such that, in contrast to an originally right angle, an open angle is formed relative to the opening direction of the vehicle body part.
As a further feature of the invention, mutually adjacent joint sections of the at least one vehicle body part and of the stationary vehicle body sections are constructed to be resistant to deformation; these joint sections extend transversely to the impact load direction and, on the face-side, in each case, connect the outer shell and the inner shell with one another. It is thereby ensured that, in the event of a corresponding vehicle impact, these joint sections forming the faces are subjected to defined kinematics and reliably carry out the desired diagonal positioning and rotation on the basis of the different deformations of the outer and inner shell.
The resistance to deformation of the outer and inner shells can be achieved by various measures, particularly by increasing the wall thickness of the outer and inner shells, by the selection of a deformation-resistant material or by correspondingly connected or integrated reinforcing structures, reinforcing shells or reinforcing plates.
The deformability of the remaining inner and outer shells can be achieved analogously by a reduction of the wall thickness or by shaping, which is weakened at least in sections, in the form of desired buckling points, folding corrugations or similar devices or also by the selection of a suitable deformable material. In all cases, the term "deformability" refers to plastic deformability by which energy can also be reduced as a result of the deformation.
Additional advantages and characteristics of the invention are found in the claims as well as in the following description of a preferred embodiment of the invention which is illustrated by way of the drawings.